"Police were called just after 0020hrs [23:20 GMT] ... to reports of a vehicle in collision with pedestrians," they said in a statement, calling the incident "major".

Neil Basu, the Metropolitan Police's deputy assistant commissioner, said the attack unfolded while a man was already receiving first aid near the mosque.

"Sadly that man has died," Basu said.

"It is too early to state if his death was a result of this attack."

Eight of the injured were taken to hospitals and the rest were treated at the scene, police said, adding that the driver of the van had also been taken to hospital. Two of the victims were severely injured, police said.

At the time of the attack, several hundred worshippers were on the streets in the area after attending prayers as part of the Muslim holy month of Ramadan.

Theresa May, UK prime minister, described the attack as a "sickening" attempt to destroy liberties that unite Britain, such as freedom of worship.

Speaking on the steps of Downing Street, May said the attack was a "reminder that terrorism, extremism, and hatred take many forms", and vowed to tackle all types of "extremism", "including Islamophobia".

"This was an attack on Muslims near their place of worship and like all terrorism, in whatever form, it shares the same fundamental goal. It seeks to drive us apart and to break the precious bonds of solidarity and citizenship that we share in this country. We will not let this happen," May said.

Jeremy Corbyn, the leader of the opposition Labour Party, also commented on the incident on Twitter.

London Mayor Sadiq Khan said the incident was an "attack on common values".

"Like the terrible attacks in Manchester, Westminster and London Bridge it is also an assault on all our shared values of tolerance, freedom and respect," he said in a statement, referring to attacks in previous months.

The UK has seen a bombing of a concert in Manchester in May, a stabbing spree earlier this month in the London Bridge area and a March attack in which a man drove a car into crowds on Westminster Bridge.

"During the night, ordinary British citizens were set upon while they were going about their lives, completing their night worship. It appears from witness accounts that the perpetrator was motivated by Islamophobia," he said.

Al Jazeera's Ben Rayner, reporting from Finsbury Park, said a police line had blocked off the typically busy Seven Sisters Road as about 100 people gathered nearby.

"There are two mosques in this Finsbury Park area - the Finsbury Park Mosque and another mosque just around the corner on Seven Sisters Road - and it appears that a number of people, worshippers, coming out of the mosque were badly injured," Rayner said.

"We don't know exactly the motivation yet," he added, noting that Finsbury Park is "well known as an area with a large Muslim population".

Men pray after a vehicle struck pedestrians near a mosque in the Finsbury Park area of north London [Neil Hall/Reuters]

Mohammed Kozbar, chairman of the Finsbury Park Mosque, said this was "a serious incident, maybe a terrorist incident, which affects a lot of people" in this part of London.

"We are in the last 10 days of [the Muslim holy fasting month of] Ramadan and a lot of people come to the mosque to pray the late prayer," he told Al Jazeera.

"These people who have been attacked were the people who just left the mosque … but we don't know whether they are all from the Muslim community - I assume that there are other casualties and victims who maybe are not even Muslim."

Local resident Hillary Briffa told Al Jazeera that "the mood on the street is very agitated".

"I reached the white van that had been pulled over and there was a man that had just been arrested and a lot of men had gathered around and shouting 'why would you do this?'"

Emergency services arrived at the scene near Finsbury Park station [Ritvik Carvalho/Reuters]